The atmosphere in Titan, Saturn's Moon, is so thick and the gravity so low, that humans could fly through it by flapping 'wings' attached to their arms.

The atmosphere in Titan, Saturn’s Moon, is so thick and the gravity so low, that humans could fly through it by flapping “wings” attached to their arms.

Titan’s atmosphere is similar to Earth’s both in the predominance of nitrogen gas and in surface pressure, which is about 1.5 bars, or 50 percent higher than sea-level pressure on Earth. However, its atmosphere is much colder, having a temperature at the surface of 94 kelvins (−290 °F, −179 °C), and it contains no free oxygen.

Combined with Titan’s low gravity—just 1/7th of Earth’s—the thickish atmosphere has led some to speculate that humans could fly under their own power with synthetic wings strapped to their arms.

Source